1. Field of the Invention
The present invention generally relates to a resistor and fabrication method thereof. More particularly, the invention relates to a resistor integrated with a transistor having a metal gate and fabrication method thereof.
2. Description of the Prior Art
To increase the performance of transistors, metal gates are commonly used in semiconductors to replace the traditional polysilicon gates as control electrodes. Two metal gate processing approaches are mainly performed: a gate first process or a gate last process. The gate last process tends to replace the gate first process, since it allows a greater choice of materials for the high-k gate dielectric layer and the metal gate.
Additionally, resistors are elements that are often used to regulate voltage and to filter noise in a circuit. The resistors usually comprise polysilicon and silicide layers.
In the current semiconductor field, the fabricating processes are continuously improved with the aim of reaching higher yields, but the integration of the manufacturing methods of those different kinds of semiconductor devices is still very complicated and difficult. Therefore, a method for fabricating a resistor integrated with a transistor having a metal gate is still needed.